“If God does not exist, everything is permitted,” wrote Fyodor Dostoevsky in The Brothers Karamazov. Mentioning this in association with Devin Patrick Kelley, the militant atheist who last Sunday perpetrated the worst church shooting in U.S. history, is bound to raises hackles. Of course, few atheists will descend into committing murder; in fact, I’ve known some I’d call “good people.” Moreover, note that I myself once not only didn’t believe in God, but like Kelley thought religious people were “stupid.” Yet is it possible a straight line can be drawn between atheism (the belief) and increasing crime and immorality? Ideas do have consequences, after all.

George Washington once wrote, “[L]et us with caution indulge the supposition that morality can be maintained without religion. …[R]eason and experience both forbid us to expect that national morality can prevail in exclusion of religious principle.” Many great thinkers have expressed the same idea, yet, when it’s related today, the assumption is that what’s being said is atheists can’t be good people. This is both because theists generally don’t explain their position well and atheists generally don’t seek to understand it well; passions run high and the two sides talk past each other. But now I’ll explain exactly what Dostoevsky and Washington meant — in a way making it apparent why it’s an insight that helped bring me, formerly a dismissive unbeliever, to faith.

A very near relation of a close friend I had said to him once, “Murder isn’t wrong; it’s just that society says it is.” I’ve heard this sentiment expressed, in different words, many times. In fact, notorious serial killer Jeffrey Dahmer, known as the “Milwaukee Cannibal,” said to his parents as a teen, “If there’s no God, why can’t I just make up my own rules?”

But here’s the question: What would you say to my friend’s relation? How could you refute him? We could warn, as a painfully legalistic ex-cop once said to me, that committing murder will land him in the pokey. But that doesn’t really address the matter’s heart, does it? We want people doing the “right thing” not just because — and when — they fear consequences. (Atheists emphasize this when criticizing the “fear of God”; note, though, there’s also the love of God.) In fact, we’ve staked our whole republic on people’s ability to, in a great measure, govern themselves from within.

I know what I can say to the man. On the surface it sounds simplistic: “You’re wrong, because God exists and has created eternal, unchanging moral law — it’s called Truth.”

Now, my friend’s relation could disagree with my proposition (God exists), but he can’t dispute my logic. If God exists and has decreed the relevant moral law, the man is wrong. Yet what can an atheist tell him? For if the atheist’s proposition that there is no God is correct, the man is correct: Society is all that’s left, so it could only be society saying “Murder is wrong.”

To fully grasp this belief’s implications, we must delve into the nature of right and wrong. If society is all there is and “Man is the measure of all things,” as ancient Greek Protagoras put it, can we even speak of “morality”? Consider my standard explanation:

If we learned that the vast majority of the world loved chocolate but hated vanilla, would we claim this made vanilla “wrong” or “evil”? Of course not. It’s just a matter of taste, or human preference. Yet how is it any different asserting murder is “wrong” or “evil” if the only reason we do so is that we learn that the vast majority of the world hates the idea of killing others in a way the vast majority of the world considers unjust?

If man’s consensus is all it is, then it falls into the same category as flavors: human preference.

Some may now say, “But wait, we’re not talking about killing my taste buds but killing people! It’s a totally different thing!” I don’t argue it doesn’t feel different (to all but sociopaths), but remember that the idea this should put murder in a different category would, under atheism, also just be a function of man’s preference.

This is irrefutable. The only way we can say “morality” properly defined — not as something synonymous with man’s preference, in other words — truly exists is if it’s a universal, eternal, unchanging moral law handed down by an omnipotent, omniscient Creator of the Universe; that is, if, just as God created Physical Reality (matter and the “laws of physics”), He also created Moral Reality.

And if God doesn’t exist? Then we should stop fooling ourselves and putting lipstick on the pig of mere preference. Stop using words such as “values” (prevalent now precisely because “morality” connotes something absolute), designed to obscure atheism’s meaninglessness. Like my friend’s relation and Dahmer, just accept that right and wrong is illusion.

This brings us to the true meaning of “You can’t be moral without God”: If divine law isn’t real, no one can be “moral” because you cannot conform to a non-existent standard. “Moral” is as incomprehensible a term in a universe without Truth as “physical” would be in one without matter. So if God doesn’t exist, neither atheists nor theists can be moral — only in or out of fashion.

So the reality, my atheist friends should note, is that embracing any moral is a matter of faith. We cannot see a moral under a microscope or a principle in a Petri dish. Science cannot prove murder (or anything else) is wrong — only possible. For science merely tells us what we can do, not what we should.

People generally don’t come to terms with these implications of atheism because most don’t take their world view to its logical conclusion; many also wouldn’t want to, for it means staring true meaninglessness in the face. It means that all the causes moderns fill their lives with are mere vanity. Tolerance can’t be better than intolerance, love better than hate, or respect for life better than murder in a godless, Moral-Truth-bereft world.

Then again, consistency can’t be better than hypocrisy, pretense better than sincerity, or fairness better than imposing one’s will, either. Thus, someone who has thought these things through and accepted atheism’s correlative moral nihilism may push his agenda simply because he wants to. As with atheist’s atheist Friedrich Nietzsche, he may blithely accept his own contradictions, boiling his creed down to occultist Aleister Crowley’s maxim, “Do what thou wilt shall be the whole of the law.”

By the way, this may explain studies showing that sociopaths have above-average intelligence. Perhaps they’re people smart enough to think these matters through, but unwise enough to come to the wrong conclusion (God doesn’t exist, thus Truth doesn’t exist, therefore right and wrong doesn’t exist). For certain is that if you accepted this parenthetical proposition intellectually — and incorporated it into yourself on an emotional level so that it permeated not just your head but your heart — you would be a sociopath. You wouldn’t have a conscience because you’d know, and feel, that there was nothing to be conscientious about.

Of course, almost no atheist so thoroughly imbibes that proposition; most have strong feelings about various trespasses (real and imagined). So not every atheist becomes a reprobate any more than every Muslim becomes a terrorist or every Nazi a genocidal maniac. But ideas have consequences. Atheism, just like misguided theism (e.g., Islam), is destructive.

This may take a dark form or just that of the atheistic but generally good-hearted young man I once knew who responded, when I mentioned that something he was contemplating was wrong, “But it’s not wrong for me.” The point, however, is that atheism’s implied moral nihilism can justify anything. Rape? Kill? Steal? Why not? Who’s to say it’s wrong? This brings us to one last matter.

And that’s the problem. Silence on moral matters would be fine if man by (fallen) nature were angelic. But by (fallen) nature he’s barbaric — and he remains so unless some civilizing agency enters the equation. Atheism’s mistake is one of omission.

This is why Dostoevsky, Dahmer and Washington were right: “If God does not exist, everything is permitted.” Ideas have consequences. Be careful what you believe — and what you espouse.